Fix: remove clients from collection

Closes: #109
PR-URL: #110

Author: tshemsedinov

lib/server.js

@@ -129,15 +129,15 @@ const listener = application => (req, res) => {
   const timer = setTimeout(() => {
     if (finished) return;
     finished = true;
-    clients.delete(res.connection);
+    clients.delete(connection);
     client.error(504);
   }, LONG_RESPONSE);
 
   res.on('close', () => {
     if (finished) return;
     finished = true;
     clearTimeout(timer);
-    clients.delete(res.connection);
+    clients.delete(connection);
   });
 
   application.logger.log(`${method}\t${url}`);